1. Field of the Invention
The present invention relates to a ceramic sheet with catalyst mainly composed of an inorganic oxide carrying a catalyst and heat resistant ceramic fibers, and more particularly to a ceramic sheet with catalyst possessing an action to oxidize and decompose organic compounds by the catalytic activity, and a method of manufacturing the same.
2. Related Art of the Invention
Recently the catalytic combustion system of burning fuel gas by catalyst has been noticed as a combustion system low in emission of environmental pollutants.
The catalyst conventionally used in catalytic combustion was carried on honeycomb ceramics of cordierite or the like. However, the porosity of honeycomb ceramics is as low as 30%, and the pressure loss is significant, and yet the degree of freedom of structure is small, and hence it was difficult to form a desired shape.
Accordingly, taking note of the free processability of commercial ceramic sheets, it has been attempted to form a catalyst layer on the surface by applying a slurry composed of an inorganic compound carrying a catalyst on a ceramic sheet.
In such conventional method, however, since the surface of the ceramic sheet is covered with an inorganic oxide, the combustion gas does not permeate widely into the inner parts of the ceramic sheet, and catalytic combustion reaction takes place only on the surface layer, and therefore the combustion efficiency is very poor.
Besides, the processability is poor because of the toughness of ceramic fibers composing the ceramic sheet, and the catalyst is hardly dispersed uniformly when dipping into the slurry containing the catalyst.
On the other hand, as a method of carrying a catalyst uniformly into inner parts, a method of immersing a ceramic sheet in a solution containing noble metal salt, and impregnating the noble metal salt in the ceramic sheet may be considered, but in this method, it is hard to carry the catalyst uniformly.
In the light of such problems of the conventional catalyst carriers, it is an object of the invention to present a ceramic sheet with catalyst high in porosity, excellent in combustion efficiency, and easy in processability into any desired shape.